In ground design should pay attention to the following:

1. Correct selection of single point grounding in general, filter capacitance public side should be the other ground coupled to the only join points, large current of interact with the primary circuit of the ground should be close to, and the corresponding circuit power filtering capacitance can also on the level ground, mainly considering the current parts back into the ground the circuit is changing, as a result of actual flows through the impedance of the line will be circuit of each part of the potential change and the introduction of interference. In this switch power supply, its inductance smaller effect between wiring and devices, and grounding circuit had a greater influence on the formation of the circulation of interference, thus using one-point earthing, the power switch current loop (a ground of several devices are connected to the ground on his feet, ground of output rectifier current loop of several devices also received the corresponding filter capacitance grounded on his feet, the power supply work more stable, not easy self-excited. When making less than a single point, in is located in the two diode or a small resistance, actually in the relatively concentration can be a piece of copper foil.2. Bold grounding line as far as possible if the ground wire is very thin, grounding potential changes over electric current, the timing signal level instability of the electronic equipment, anti-noise performance is bad, so be sure to every large current earthing end USES short and wide printing line as far as possible, try to widen the power supply, ground wire width, it is best to ground wide than the power cord, their relationship is: ground > power > signal lines, if possible, the width of the ground wire should be greater than 3 mm, also can use copper layer on the ground a large area, all the places are not used on the PCB as earth wire connected to ground. For global wiring, still must follow the following principles:(1). Wiring direction: look from the surface of welding, the arrangement of the components bearing as far as possible to keep consistent with schematic diagram, wiring should take line direction is consistent with the circuit diagram, because of the production process often need to test the various parameters on surface of the welding, so do check in for production, debug and repair (note: refers to the circuit performance and under the premise of the machine installation and panel layout requirements).(2). The wiring diagram design must line, bend as less as possible on the printing of arc line width don't mutations, wire corner should be 90 degrees or higher, line is straightforward.(3). In printed circuit does not allow to have the cross circuit, that may cross the line, can use the "diamond", "round" two ways to solve. Is to let a lead from another resistor, capacitor, transistor at the foot of the space "diamond" in the past, or crossing from one of the lead at one end of the "around" in the past, under special circumstances how circuit is complex, to simplify the design also allows for wire jumper, solve the problem of cross circuit. Due to adopting single panel, upright components located on the top surface, table device located on the bottom surface, so when the layout of the upright device can is it stick to device overlap with the table, but avoid overlap welding plate.3. The input fields and output for the low voltage DC - DC switching power supply, to the output voltage feedback back to transformer primary and should have a common reference to on both sides of the circuit, so after the shop on the ground on both sides of the copper, even together, forming a common ground.